Deburring apparatus

ABSTRACT

The disclosure is of apparatus and method for deburring the inner surface  a metal tube by inserting a tubular structure into the metal tube and flowing an abrasive medium along a path over the area to be deburred and out of the metal tube.

The invention described herein may be manufactured, used and licensed byor for the Government of the United States for governmental purposeswithout the payment of any royalties thereon.

This application is a continuation of application Ser. No. 07/825,366,filed Jan. 24, 1992, now abandoned.

BACKGROUND OF THE INVENTION

In the manufacture of a weapon having a bore such as a rifle, lands areformed inside the barrel and it is generally necessary to remove sharpedges from the rifling lands at the origin of the bore. It is alsonecessary to provide the required radius of the rifling lands.

One method of removing sharp edges from rifling lands at the origin ofthe bore is known as a whipping procedure. In this procedure, emerypaper is secured to a metal rod which is coupled to an electric drillfor turning the rod. The rod is inserted in the barrel and the emerypaper is rotated at the rifling land to provide the desired smoothing.This method is unsatisfactory because it is time consuming and does notperform the required radiusing of the lands.

SUMMARY OF THE INVENTION

The apparatus of the invention includes means for passing an abrasivefluid through a bore with such control that uniform smoothing of landsand uniform radiusing are achieved.

DESCRIPTION OF THE DRAWINGS

The drawing is a side sectional elevational view of apparatus embodyingthe invention.

DESCRIPTION OF THE INVENTION

The apparatus of the invention is used to smooth burrs on rifling lands10 and to radius the lands in the origin of the bore 20 of a rifle orsimilar weapon 30. The deburring apparatus 40 is a tubular member whichincludes an annular outer tube 50 and a central tube 60 and is adaptedto be inserted into the bore of the weapon to be deburred and radiused.The terms "radius" is used occasionally as a verb throughout thisapplication, as in "to radius" a tube, or "radiusing" e.g. The meaningis to smoothly round sharp edges here for example in a precision way, toa particular (diameter) radius. The application given here is to smoothout the sharp edges of a rifling pattern (like internal threads) cutinto the bore of a weapon. The space 230 between outer tube 50 andcentral tube 60 provides a path for a fluid medium as will be explainedbelow. The deburring apparatus has a front end 70 and a rear end 80.

The rear end 80 of the deburring apparatus 40 which is adapted to bepositioned adjacent to the rifling lands to be radiused includes a firstannular wall and mechanical seal 90 at which the outer annular tube 50terminates and through which the inner central tube 60 passes. Themechanical seal 90 includes a plurality of apertures 100 which are incommunication with the outer annular tube 50. The mechanical seal wallor connector 90 includes an annular sealing ring 95 secured to its rearsurface. The sealing ring has a diameter such that it fits snugly in thepowder chamber 25 of the weapon.

Spaced from the mechanical seal 90 is a front seal assembly whichincludes second annular wall or plate 110, of a diameter to fit snuglyin the weapon bore. The front seal assembly also includes an annulargasket 115 disposed against the surface of plate 110 which faces wall90.

Between the first and second walls 90 and 110 is placed a part 120 knownas a medium compression head. This compression head is generally annularand includes a central bore into which the central tube 60 extends in atight fit. The annular member 120 has a central portion 121 of adiameter such that its outer wall 130 is disposed suitably close to thewall of the weapon bore at the rifling lands 10 to be radiused. Theannular member or compression head 120 includes a first annular portion121 and a second annular portion 150 on either side thereof. The firstannular portion 121 is spaced a small distance from the seal wall 90 andthe second annular portion 150 bears against the seal wall or plate 110.Where the central portion 121 of annular member 120 meets the secondannular portion 150, it is provided with a plurality of apertures 160arrayed in an annular pattern which communicate with the bore of theannular member 120 and the central tube 60. The annular portion 121 issealed to the central tube 60 by a sealing means 195.

In operation of the deburring apparatus 40, the apparatus 40 is insertedin the bore of the weapon having rifling lands to be deburred andradiused with the central portion 121 of the annular member 120 disposedat the rifling lands. The apparatus 40 is supported and centered byannular guides 170 disposed along its length, as required. A source 180of an abrading medium comprised of a carbide silicone based materialimpregnated with various size grains of carbide chips is provided and iscoupled by suitable hosing to the quick release connector 175 secured toannular outer tube 50 and the central tube 60 so that the medium canflow into the central tube. Suitable hosing is also connected to a quickrelease connector 190 provided on central tube 60. The fluid mediumflows, under pressure, down the annular tube 50, through the apertures100 in the wall 90 along the outer surface 130 of the annular member 120and across the rifling lands 10 and through the apertures 160 in thesecond annular 150 and into the central tube 60 and out 190, thereafterback to the source 180 of the fluid medium (fluid recycling recoverymechanism not shown). This operation is continued until the riflinglands are properly radiused. Normally, this operation can be completedin a time of the order of four to six hours.

All parts of the deburring apparatus 40 are preferably of aluminumexcept for certain parts which are of hardened steel where required. Theannular compression head 120 is treated to a 0.0005 hardcoating. A plate185 serves to support the deburring apparatus in general, and furtherserves to support the apparatus for insertion into the tube for thedeburring operation.

What is claimed is:
 1. Device for cutting and smoothing surfaces andedges of the interior lands (10) of a metal gun barrel tube by action ofabrasive liquid, comprising:first insertable cylindrical tubular means(50) sized to fit essentially within said metal gun barrel tube (30),and a first flange means (90) attached on one end of said first tubularmeans, sealed with a ring means (95) to prevent liquid from entering anyof the space (25) between the first tubular means (50) and the barreltube (30); and second insertable cylindrical tubular means (60)concentrically positioned within said first tubular means (50), sized sothat there is an open annular passageway (230) between said first andsecond tubular means mounted through a hole in said first flange means(90); and a plate means (110) fitted on one end of said barrel (30) toseal it to contain liquid; a liquid pressure head attachment (120)fitted to the end of said second tubular means (60), said endterminating, and said pressure head (120) located in, the space betweensaid first flange means (90) and said plate means (110); apertures (100)in said flange means to permit liquid to pass out from said open annularpassageway between said first and second tubular means; means (180)located at the end of said respective first and second tubular meansopposite said plate means for pumping abrasive liquid under pressureinto said open annular passageway (130) between said first and saidsecond tubular means, said first and second tubular means being bothsealed at their respective ends opposite the said plate means (110) toprevent the escape of liquid at those respective ends; whereby saidabrasive liquid is pumped through said passageway (130) between saidfirst and said second tubular means, through said aperture (100) intothe space bounded between said flange (90) and said plate (110) and theinside of the barrel (30) around said pressure head (120) to abrade butnot to deform the inside of the barrel (30) at the location of lands(10) within the barrel which require smoothing then inside the pressurehead into the second tubular means (60), said second tubular mean havinga further means (190) for bleeding out the abrasive liquid therefrom. 2.The device of claim 1, wherein the pressure head (120) is comprised ofan annular cylindrical head piece (121) sealed to said second tubularmeans (60) by a sealing means (195) and further including a pressureportion (150) which is attached to plate (110) between head piece (121)and said plate (110).
 3. The device of claim 1 wherein said firsttubular means (50) is supported within said gun barrel (30) by a supportstructure (170).